Operaciones de Flujo de Fluidos. Tema 6: Flujo externo

Flujo externo. El tema resume las principales características del flujo externo fluido-partícula. Trata tanto del movimiento de las partículas sólidas en el seno de un fluido como del flujo del fluido a través de lechos porosos, tanto fijos como fluidizados

Operaciones de Flujo de Fluidos. Tema 5: Medida de caudales

Apuntes del tema 5. Medida de caudales. En este tema se resumen las principales características de los medidores de caudal, analizando de manera especial los que basan su medida en diferencias de presión

Evaluación de la fermentación acidoláctica de la masa para productos de panificación con inclusión de quinua (Chenopodium quinoa Willd)

La presente investigación se llevó a cabo con el objetivo de determinar la influencia de la fermentación acidoláctica en las propiedades mecánicas de masas de quinua y las características de calidad de sus productos de panificación como sustituto parcial del trigo. Se evaluó la composición y comportamiento en la panificación de harinas de las variedades de quinua: Tunkahúan, Facianar Aurora y Blanca de Jericó; en sustituciones del 20, 40 y 60% de la harina de trigo. La variedad Facianar Aurora presentó la mejor aptitud tecnológica permitiendo obtener panes de buenas características nutricionales, y de volumen, color y textura con una sustitución máxima del 40%. La fermentación acidoláctica con tres cultivos iniciadores homofermentativos afectó la composición y disminuyó la resistencia a la deformación de masas de esta variedad. Tanto el cultivo iniciador como el porcentaje de adición de masa ácida tuvieron efecto en las características de calidad, nutricionales y sensoriales de los panes obtenidos.Abstract. This research was made with the aim to determinate acidolactic fermentation influence on quinoa dough’s mechanical properties and the quality characteristics of its breadmaking products as a wheat partial substitute. Composition and breadmaking performance of flours from the quinoa cultivars: Facianar Aurora, Blanca de Jericó and Tunkahúan were evaluated, with wheat substitutions of 20, 40 and 60%. Facianar Aurora showed the best breadmaking performance obtaining breads with good nutritional, volume, color and texture characteristics with a 40% maximum substitution. Acidolactic fermentation with three homofermentative commercial starters affected composition and reduced quinoa dough strain resistance. Starter culture and sourdough level in the batter showed a high influence on bread´s quality, sensory and nutritional traits.Maestrí

Experimental study of concentration polarization in a crossflow reverse osmosis system using Digital Holographic Interferometry

Digital Holographic Interferometry (DHI) has been used to visualize the polarization concentration layer during crossflow RO. This technique is based on the fact that changes in the concentration of the solution produce changes in its refractive index. Therefore, the concentration profile formed due to the polarization phenomenon can be visualized as interference fringes. Experiments with Na2SO4 and NaCl solutions have been carried out. Three variables of the process were studied: crossflow velocity, initial concentration and pressure applied. In each experiment, crossflow velocity was changed every 30min, in an increasing or decreasing sequence. Few minutes after changing the crossflow velocity the steady-state was reached. Interference fringe patterns of the polarization layer and their corresponding concentration profiles, as well as the permeate flux in different experimental conditions, are presented. The major experimental result is the visualization for the first time in situ and in real-time of the polarization layer in a process of crossflow by a non-invasive method. Experimental results show a close relationship among crossflow velocity, permeate flux and polarization layer. Furthermore, experimental maximum concentration values reached at the membrane surface were compared with values calculated by using the film theory approach and a good agreement was obtained.This research has been sponsored by the Plan Nacional de I+D+I CTQ2006-14904 (Ministerio de Ciencia e Innovación) and Generalitat Valenciana, Consellería de Educación (ACOMP/2009/366)

Water Distribution Networks Optimization Considering Uncertainties in the Demand Nodes

The fluctuation in the consumption of treated water is a situation that distribution networks gradually face. In times of greater demand, this consumption tends to suffer unnecessary impacts due to the lack of water. The uncertainty that occurs in water consumption can be mathematically modeled by a finite set of scenarios generated by a normal distribution and attributed to the network design. This study presents an optimization model to minimize network installation and operation costs under uncertainties in water demands. A Mixed Integer Nonlinear Programming model is proposed, considering the water flow directions in the pipes as unknown. A deterministic approach is used to solve the problem in three steps: First, the problem is solved with a nominal value for each uncertain parameter. In the second stage, the problem is solved for all scenarios, with the independent variables of the scenario being fixed and obtained from the solution reached in the first stage, known as the deterministic solution. Finally, all scenarios are solved without fixing any variable values, in a stochastic approach. Two case studies were used to test the applicability of the model and global optimization techniques were used to solve the problem. The results show that the stochastic solution can lead to optimal solutions for robust and flexible water distribution networks, capable of working under different conditions, considering the uncertainties of node demand and variable pipe directions.The authors gratefully acknowledge the financial support from the National Council for Scientific and Technological Development (Brazil), process 309026/2022-9

Sustainable supply chain design under correlated uncertainty in energy and carbon prices

This paper aims to provide an improvement in the modeling of supply chain designs by incorporating correlated uncertainty among multiple parameters, resulting in a more resilient design. A new methodology to generate forecasts for historically correlated time series, regardless of their underlying probability distributions, is presented and applied to generate scenarios for energy and carbon prices, which historically proved to be correlated. These scenarios are then used in a stochastic computation to obtain a three-echelon supply chain design in Europe maximizing the economic performance. The emissions were monetarized through the incorporation of the European Union cap-and-trade emissions trading system into the model. The social impact of the supply chain network is measured in terms of the direct, indirect and induced jobs it creates, which are proportional to the economic performance. By combining the developed methodology with data mining algorithms, a reduction in the number of required scenarios by more than 90% was achieved. The numerical case study moreover shows that the stochastic design ensures an average reduction of emissions by more than 3 ktons compared to the use of a deterministic approach. In comparison, the computation of a stochastic supply chain design without parameter correlation takes 5 times longer.The authors gratefully acknowledge financial support to the Conselleria de Innovacion, Universidades, Ciencia y Sociedad Digital of the Generalitat Valenciana, Spain, under project PROMETEO/2020/064 and project PID2021-124139NB-C21

Design of a Cooperative Sustainable Three-Echelon Supply Chain under Uncertainty in CO2 Allowance

Driven by the growing concern regarding greenhouse gas emissions, in this work, we provide a robust stochastic model for the design of a cooperative supply chain (SC) under uncertainty in CO2 allowance prices from the European Union Emissions Trading System (EU ETS). During the last years, CO2 allowance prices have undergone unexpected changes, having strong impact on the design and management of optimal SC. The consideration of uncertainty in the allowance prices has therefore become more important. We use an autoregressive integrated moving average (ARIMA) model to predict future allowance prices. A full discretization of the underlying probability space leads to a number of scenarios far too large to be handled, so we compare two approaches to reduce the number of scenarios to a feasible maximum, the ScenRed algorithm and K-means clustering. The obtained results are compared with a deterministic approach that is widely studied in the literature, showing an increase in the benefits and a reduction of emissions.The authors gratefully acknowledge financial support to the Conselleria de Innovacion, Universidades, Ciencia y Sociedad Digital of the Generalitat Valenciana, Spain, under project PROMETEO/2020/064

Water Management in Shale Gas: A Perspective from the Cooperative Games Theory

This project has received funding from the European Union's Horizon 2020 Research and Innovation Program under grant agreement No. 640979

Systematic Tools for the Conceptual Design of Inherently Safer Chemical Processes

Society is continuously facing challenges for safer chemical plants design, which is usually driven by economic criteria during the early steps of the design process, relegating safety concerns to the latest stages. This paper highlights the synergy of merging Process System Engineering tools with inherent safety principles. First, we design a superstructure that comprises several alternatives for streams, equipment, and process conditions, which exhibit different performance of economic and inherently safer indicators, the total annualized cost, and the Dow’s Fire and Explosion Index, respectively. The solution to this multiobjective problem is given by a Pareto set of solutions that indicates the existing trade-off between both objectives. The capabilities of the proposed framework are illustrated through two case studies, which solutions provide valuable insights into the design problem and are intended to guide decision-makers toward the adoption of inherently safer process alternatives.The authors acknowledge financial support from “Proyectos de l+D para grupos de investigación emergentes GV/2016/005” (Conselleria d’Educació, Investigació, Cultura i Esport, GENERALITAT VALENCIANA) and from the Spanish “Ministerio de Economía, Industria y Competitividad” (CTQ2016-77968-C3-02-P, AEI/FEDER, UE)

Shale Water Desalination: Multistage membrane distillation considering different configurations and heat integration

This work introduces a simultaneous synthesis of membrane distillation systems with heat exchanger networks (HENs) for desalinating shale gas flowback and produce water. The direct contact and vacuum membrane configurations are the best options for desalination. Moreover, multistage membrane distillation systems usually have higher efficiencies than single-stages processes. For this reason, two different mathematical models for synthetizing multistage direct contact membrane distillation (MSDCMD) and multistage vacuum membrane distillation (MSVMD) are developed and optimized to achieve zero liquid discharge (ZLD) conditions. To this aim, brine discharges are considered to be near to the salt saturation conditions. The multi-stage superstructures are implemented in GAMS and optimized by SBB solver. The mathematical model is formulated via generalized disjunctive programming (GDP) and mixed-integer nonlinear programming (MINLP), to minimize the total annualized cost.This project has received funding from the European Union’s Horizon 2020 Research and Innovation Programme under grant agreement No. 640979